A colorectal polyp is an abnormal growth of tissue on the inside lining of the colon or rectum.
Colorectal polyps are very common. They affect about 25% of adults who are 50 years of age and older. They are most often benign, or noncancerous. However, polyps can sometimes develop into colorectal cancer.
The exact cause of polyps is not well understood. Sometimes polyps are genetic. Polyps are more common as a person gets older. Diets high in fat and low in fiber are thought to play a role in causing polyps. Alcohol use, cigarette smoking, and obesity may also increase the risk of developing polyps.
Most often, polyps cause no symptoms at all. They are found when a healthcare provider examines the colon. Rarely, polyps can cause blood in the stools or abdominal distress.
Colorectal polyps can be seen only with special tests because polyps are hidden within the body. A barium enema is a special X-ray test that can detect polyps.
Starting at the age of 40, people should have yearly digital rectal exams and stool testing for occult blood. Annual fecal occult blood tests allow early detection of colorectal polyps. The polyps can then be removed before they become colorectal cancer.
Beginning at the age of 50, a flexible sigmoidoscopy should be done every 3 to 5 years. A sigmoidoscopy is a procedure that allows a healthcare professional to look into the rectum and sigmoid colon through a flexible scope.
A colonoscopy may also be used to diagnose colorectal polyps. Like a sigmoidoscopy, this procedure allows a healthcare professional to look into the rectum and sigmoid colon through a flexible scope. The difference between the procedures is that colonoscopy goes further or deeper into the bowels than sigmoidoscopy.
Currently, nothing has been shown to definitely reduce the risk of polyps. Diets high in fiber, folic acid and calcium, and low in fat may help to reduce the risk. Nonsteroidal anti-inflammatory medications may also reduce the risk of developing colorectal polyps.
Colorectal polyps sometimes become colorectal cancer. Occasionally, a polyp actually is a small, early cancer.
Colorectal polyps are not contagious and pose no risk to others.
When polyps are seen with a barium enema X-ray test, the person may need a sigmoidoscopy or colonoscopy. During these procedures, the healthcare provider can sometimes remove or destroy polyps through the tube. Otherwise, the provider may cut off a small piece of the polyp for a biopsy to be looked at under a microscope.
In some cases, a portion of the colon is removed surgically, with a colostomy. This is usually done if the polyp is large, or if the biopsy looks suspicious under the microscope.
Colonoscopy and sigmoidoscopy involve a risk of tearing a hole in the bowel, bleeding, and infection. This risk is increased when biopsies are taken. Any surgery involves a risk of infection, bleeding, and allergic reaction to anesthesia.
After a polyp is treated, the person can generally go back to his or her normal activities. The healthcare provider will recommend a follow-up plan based on the type of polyps a person has.
All persons are advised to have regular screening for colorectal polyps and colorectal cancer after the age of 50. Those with polyps will need more frequent future screenings with either colonoscopy or barium enema.
Author:Adam Brochert, MD
Date Written:
Editor:Ballenberg, Sally, BS
Edit Date:12/31/00
Reviewer:Eileen McLaughlin, RN, BSN
Date Reviewed:07/02/01
Gastrointestinal and Liver Disease, 1998, Sleisenger et al